WASHINGTON, March 15 (Reuters) - Saudi Arabia's military
intervention in Bahrain has exposed a diplomatic rift as Riyadh
and Washington make different calculations over a crisis that
could have a far-ranging impact on their relations.

Close Saudi-U.S. ties anchor stability in the oil-rich Gulf.
The autocratic Sunni Muslim monarchy provides 12 percent of U.S.
crude imports and serves as a powerful regional counterweight to
Shi'ite-ruled Iran, a defiant U.S. foe.

But when Saudi troops rolled across the causeway into
neighboring Bahrain on Monday to buttress the embattled Sunni
royal family against protests by the island's Shi'ite Muslim
majority, Washington scrambled to respond as its own repeated
pleas for negotiation appeared to have been swept aside.

"This is the tightrope the administration has to walk," said
Kenneth Pollack, a Middle East expert at the Brookings
Institution, a Washington think tank.
Continued...